12g spokes are really hard to find in stainless. the only thing i could think of is try older bike shops, they might have some lying around. i dunno anyone who makes them anymore except the chinese, and they're UCP (universal chrome plated.)
i bought some Husky 11g's, and the chrome on them is pretty lousy. the wheels are on the next bike i'm gonna motor up as soon as summer's over, and i've been riding the bike to the beach all summer. the spokes already show signs of corrosion. nothing major, but still...
granted, it's damp, salty air, but my motorbike with chrome worksman spokes gets more use in this weather, and those spokes are still shiny.
those cheap chinese wheels with the 12g spokes? i put some on my buddy's beach cruiser in march. hang on, lemme go take a picture of them...
this bike sits outside at his work in Newport Beach most of the day, but still. i've had beach bikes in the good old days of american chrome that took 5 years to get this bad...